The Holosun 509PLT-MOS9MM is a genuine Holosun adapter plate that mounts a 509T-footprint enclosed red dot sight — the HS509T X2, HE509T X2 or HE509T-X2-GD — onto Glock MOS optics-ready slides in 9mm, including the G17, G19, G34 and G45 MOS. The plate and the correct screws for both plate-to-slide and optic-to-plate are supplied together.
The 509T uses Holosun's own rear-lug footprint rather than the RMR or RMSc pattern, so it will not bolt straight onto a factory optic cut. This plate is the part that bridges the two.
How It Compares
For a CZ P-10 host use the 509PLT-CZP10 plate, and for an RMR-cut slide use the 509PLT-507C plate. If your optic is a K-series rather than a 509T, see the K mounting plate for Glock MOS 9mm. Our Glock MOS optic fitting guide walks through the whole job.
Ideal For
- Airsoft gas blowback pistol builds that use a Glock MOS slide
- Section 1 long-barrelled pistols and revolvers built on a Glock MOS pattern
- Licensed pistol setups in Northern Ireland and target work overseas
- Training and dry-practice rigs where the optic needs to move between hosts
Key Features
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Optic Footprint: Holosun 509T rear-lug footprint, not RMR and not RMSc
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Host: Glock MOS optics-ready slides (9mm models)
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Hardware: plate-to-slide and optic-to-plate screws supplied
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Build: genuine Holosun part, machined to Holosun's own tolerances
Technical Specifications
| Optic Footprint |
Holosun 509T footprint (HS509T / HE509T) |
| Fits |
Glock MOS optics-ready slides, 9mm models |
| Hardware |
Mounting screws included (plate-to-slide and optic-to-plate) |
| MPN / UPC |
509PLT-MOS9MM / 810047071020 |
What's Included
- Holosun 509PLT-MOS9MM mounting plate
- Plate-to-slide and optic-to-plate mounting screws
UK Delivery & Support
Imported from the USA, duty paid by us, and dispatched tracked from the UK — nothing to pay on delivery — backed by UK-based support.
Frequently Asked Questions
Which optics does the Holosun 509PLT-MOS9MM plate fit?
The Holosun 509PLT-MOS9MM plate fits optics with the Holosun 509T footprint, which means the HS509T X2, the HE509T X2 and the HE509T-X2-GD. It does not fit RMR-footprint optics such as the 507C or 407C, and it does not fit RMSc-footprint optics such as the 507K or 407K.
Which slides does the Holosun 509PLT-MOS9MM plate fit?
The Holosun 509PLT-MOS9MM plate fits Glock MOS optics-ready slides in 9mm that use Glock's standard MOS plate system, including the G17, G19, G34 and G45 MOS.
Are the mounting screws included with the Holosun 509PLT-MOS9MM?
Yes. The Holosun 509PLT-MOS9MM is supplied with both sets of screws — those that fix the plate to the slide, and those that fix the optic to the plate.
Is the 509T footprint the same as RMR or RMSc?
No. The Holosun 509T uses a rear-lug footprint unique to Holosun's 509 series. RMR is the larger Trijicon pattern used by the 507C and 407C, and RMSc is the smaller Shield pattern used by the 507K and 407K. Our pistol red dot footprint compatibility chart sets out which optic fits which cut.
